Semiconductor devices are used in many electronic and other applications. Semiconductor devices comprise integrated circuits that are formed on semiconductor wafers by depositing many types of thin films of material over the semiconductor wafers, and patterning the thin films of material to form the integrated circuits.
Inductors are passive devices that are widely used in many applications. Integrated inductors are usually formed using conventional semiconductor processes. While improvements in performance of inductors are constantly sought, there is also a demand in semiconductor device technology to integrate many different functions on a single chip, e.g., manufacturing various types of active and passive devices on the same die.
As an example, ferrite bead inductors are used in many applications such as cellular phone or music players as electromagnetic interference (EMI) protection devices. Inductors are also used in DC/DC converters to smooth the voltage output and are manufactured as discrete SMD devices. However, there is an increasing demand for increasing the number of inductors, and hence there is a need to integrate inductors within the same package as the integrated circuits to be protected.
However, such integration creates additional challenges that need to be overcome. For example, conventional inductive structures require large surface areas or have limited magnetic performance. For aggressive integration, it is essential to have a low surface area along with a high quality factor.
In one aspect, the present invention provides a structure and method of forming inductors having high inductivity and low resistivity without a significant increase in production costs.